WASHINGTON (NewsNation) — Two of Hunter Biden‘s former business partners testified before the House Oversight Committee Wednesday as part of the GOP’s impeachment probe of President Joe Biden.

House Oversight Committee Chairman James Comer, R-Ky., signaled an interest in approaching the impeachment probe from another direction, saying the committee’s inquiry against the president has reached the point of possible criminal referrals.

“What is apparent, after over a year of investigation, is that the Bidens do not work in any traditional sense of the word,” Comer said.

Republican members of the panel have alleged the president and his family financially benefitted from policy decisions that were made while Joe Biden was vice president. However, the panel has yet to produce any tangible evidence of impropriety.

Comer said Wednesday that he plans to invite President Biden to testify before the committee. The White House did not respond to a NewsNation request for comment.

During the hearing, Comer accused the president himself of being the brand being sold and advertised by the Biden family, explaining that relations with Joe Biden are what Hunter Biden sells. Lawmakers shared what they believed to be “evidence” that Joe Biden allegedly lied about his involvement in Hunter’s business dealings.

“Either Joe Biden is complicit, or Joe Biden is incompetent,” Comer said.

Lawmakers questioned two of Hunter Biden’s former associates and a witness secured by Democrats.

Republican’s first witness, Tony Bobulinski, who once worked with Hunter Biden during a venture with a Chinese energy company, talked about referencing a 10% cut for “the big guy” in an email. House Republicans believe “the big guy” to be Joe Biden.

The second witness for Wednesday’s hearing, Jason Galanis, testified remotely from prison, where he is serving time for fraud.

Hunter Biden has said he only met Galanis once, but House Republicans could ask him about times the president’s son included his father in calls during meetings with business associates.

Businessman Lev Parnas, a former aide to Rudy Giuliani, testified as a House Democrat witness. Parnas also spent time behind bars for fraud and campaign finance crimes.

Parnas claims he never found any dirt on the Bidens while investigating their connections to Ukraine. He also remains critical of this investigation, accusing former President Donald Trump’s team of pushing information allegedly known to be false.

Regarding the possible criminal referrals, Comer has not said who could face them.

The president’s son declined to attend the hearing but has maintained his father never made money from his business dealings. House Republicans want to see if Hunter Biden’s former associates have evidence against that claim.

Last week, the White House told the House to drop any impeachment inquiries against the president. There has also been a lack of political appetite within the Republican ranks to go forward with an actual impeachment.